Inbred corn line PHK35

ABSTRACT

According to the invention, there is provided an inbred corn line, designated PHK35. This invention thus relates to the plants and seeds of inbred corn line PHK35 and to methods for producing a corn plant produced by crossing the inbred line PHK35 with itself or with another corn plant. This invention further relates to hybrid corn seeds and plants produced by crossing the inbred line PHK35 with another corn line or plant and to crosses with related species.

FIELD OF THE INVENTION

This invention is in the field of corn breeding, specifically relatingto an inbred corn line designated PHK35.

BACKGROUND OF THE INVENTION

The goal of plant breeding is to combine in a single variety/hybridvarious desirable traits. For field crops, these traits may includeresistance to diseases and insects, tolerance to heat and drought,reducing the time to crop maturity, greater yield, and better agronomicquality. With mechanical harvesting of many crops, uniformity of plantcharacteristics such as germination and stand establishment, growthrate, maturity, and fruit size, is important.

Field crops are bred through techniques that take advantage of theplant'method of pollination. A plant is self-pollinated if pollen fromone flower is transferred to the same or another flower of the sameplant. A plant is cross-pollinated if the pollen comes from a flower ona different plant.

Plants that have been self-pollinated and selected for type for manygenerations become homozygous at almost all gene loci and produce auniform population of true breeding progeny. A cross between twohomozygous lines produce a uniform population of hybrid plants that maybe heterozygous for many gene loci. A cross of two plants eachheterozygous at a number of gene loci will produce a population ofhybrid plants that differ genetically and will not be uniform.

Corn plants (Zea mays L.) can be bred by both self-pollination andcross-pollination techniques. Corn has separate male and female flowerson the same plant, located on the tassel and the ear, respectively.Natural pollination occurs in corn when wind blows pollen from thetassels to the silks that protrude from the tops of the incipient ears.

The development of corn hybrids requires the development of homozygousinbred lines, the crossing of these lines, and the evaluation of thecrosses. Pedigree breeding and recurrent selection breeding methods areused to develop inbred lines from breeding populations. Breedingprograms combine the genetic backgrounds from two or more inbred linesor various other broad-based sources into breeding pools from which newinbred lines are developed by selfing and selection of desiredphenotypes. The new inbreds are crossed with other inbred lines and thehybrids from these crosses are evaluated to determine which of thosehave commercial potential.

Pedigree breeding for single-gene traits starts with the crossing of twogenotypes, each of which may have one or more desirable characteristicsthat is lacking in the other or which complement the other. If the twooriginal parents do not provide all of the desired characteristics,other sources can be included in the breeding population. In thepedigree method, superior plants are selfed and selected in successivegenerations. In the succeeding generations the heterozygous conditiongives way to homogeneous lines as a result of self-pollination andselection. Typically in the pedigree method of breeding five or moregenerations of selfing and selection is practiced: F₁ →F₂ ; F₂ →F₃ ; F₃→F₄ ; F₄ →F₅, etc.

Backcrossing can be used to improve an inbred line. Backcrossingtransfers a specific desirable trait from one inbred or source to aninbred that lacks that trait. This can be accomplished for example byfirst crossing a superior inbred (A) (recurrent parent) to a donorinbred (non-recurrent parent), which carries the appropriate gene(s) forthe trait in question. The progeny of this cross is then mated back tothe superior recurrent parent (A) followed by selection in the resultantprogeny for the desired trait to be transferred from the non-recurrentparent. After five or more backcross generations with selection for thedesired trait, the progeny will be heterozygous for loci controlling thecharacteristic being transferred, but will be like the superior parentfor most or almost all other genes. The last backcross generation wouldbe selfed to give pure breeding progeny for the gene(s) beingtransferred.

A single cross hybrid corn variety is the cross of two inbred lines,each of which has a genotype which complements the genotype of theother. The hybrid progeny of the first generation is designated F₁. Inthe development of hybrids only the F₁ hybrid plants are sought.Preferred F₁ hybrids are more vigorous than their inbred parents. Thishybrid vigor, or heterosis, can be manifested in many polygenic traits,including increased vegetative growth and increased yield.

The development of a hybrid corn variety involves three steps: (1) theselection of plants from various germplasm pools; (2) the selfing of theselected plants for several generations to produce a series of inbredlines, which, although different from each other, each breed true andare highly uniform; and (3) crossing the selected inbred lines withunrelated inbred lines to produce the hybrid progeny (F₁). During theinbredding process in corn, the vigor of the lines decreases. Vigor isrestored when two unrelated inbred lines are crossed to produce thehybrid progeny (F₁). An important consequence of the homozygosity andhomogeneity of the inbred lines is that the hybrid between any twoinbreds will always be the same. Once the inbreds that give a superiorhybrid have been identified, the hybrid seed can be reproducedindefinitely as long as the homogeneity of the inbred parents ismaintained.

A single cross hybrid is produced when two inbred lines are crossed toproduce the F₁ progeny. A double cross hybrid is produced from fourinbred lines crossed in pairs (A×B and C×D) and then the two F₁ hybridsare crossed again (A×B)×(C×D). Much of the hybrid vigor exhibited by F₁hybrids is lost in the next generation (F₂). Consequently, seed fromhybrid varieties is not used for planting stock.

Corn is an important and valuable field crop. Thus, a continuing goal ofplant breeders is to develop high-yielding corn hybrids that areagronomically sound based on stable inbred lines. The reasons for thisgoal are obvious: to maximize the amount of grain produced with theinputs used and minimize susceptibility to environmental stresses. Toaccomplish this goal, the corn breeder must select and develop superiorinbred parental lines for producing hybrids. This requiresidentification and selection of genetically unique individuals which ina segregating population occur as the result of a combination ofcrossover events plus the independent assortment of specificcombinations of alleles at many gene loci which results in specificgenotypes. Based on the number of segregating genes, the frequency ofoccurrence of an individual with a specific genotype is less than 1 in10,000. Thus, even if the entire genotype of the parents has beencharacterized and the desired genotype is known, only a few if anyindividuals having the desired genotype may be found in a large F₂ or S₀population. Typically, however, the genotype of neither the parents northe desired genotype is known in any detail.

SUMMARY OF THE INVENTION

According to the invention, there is provided a novel inbred corn line,designated PHK35. This invention thus relates to the seeds of inbredcorn line PHK35, to the plants of inbred corn line PHK35, and to methodsfor producing a corn plant produced by crossing the inbred line PHK35with itself or another corn line. This invention further relates tohybrid corn seeds and plants produced by crossing the inbred line PHK35with another corn line or a related species.

DEFINITIONS

In the description and examples that follow, a number of terms are usedherein. In order to provide a clear and consistent understanding of thespecification and claims, including the scope to be given such terms,the following definitions are provided:

BAR PLT=BARREN PLANTS. This is the number of plants per plot that werenot barren (lack ears).

BRT STK=BRITTLE STALKS. This is a measure of the stalk breakage near thetime of pollination, and is an indication of whether a hybrid or inbredwould snap or break near the time of flowering under severe winds. Dataare presented as percentage of plants that did not snap.

BU ACR=YIELD (BUSHELS/ACRE). Actual yield of the grain at harvestadjusted to 15.5% moisture. ABS is in absolute terms and % MN is percentof the mean for the experiments in which the inbred or hybrid was grown.

CLD TST=COLD TEST. This is the percentage of kernels that germinateunder cold soil conditions. ABS=absolute measurement and % MN ispercentage of mean of the experiments in which inbred or hybrid wasgrown.

COB SC=COB SCORE. The cob score is a rating of how well the grain isshelled off the cob and how badly the cob is broken up going through thecombine. This is given as a 1 to 9 score with 9 being very good. A highscore indicates that the grain shells off of the cob well, and the cobdoes not break.

DRP EAR=DROPPED EARS. This is a measure of the number of dropped earsper plot and represents the percentage of plants that did not drop earsprior to harvest.

EAR HT=EAR HEIGHT. The ear height is a measure from the ground to thetop developed ear node attachment and is measured in inches.

EAR SZ=EAR SIZE. A 1 to 9 visual rating of ear size. The higher therating the larger the ear size.

EST CNT=EARLY STAND COUNT. This is a measure of the stand establishmentin the spring and represents the number of plants that emerge on a perplot basis for the inbred or hybrid.

GDU SHD=GDU TO SHED. The number of growing degree units (GDUs) or heatunits required for an inbred line or hybrid to have approximately 50percent of the plants shedding pollen and is measured from the time ofplanting. Growing degree units are calculated by the Barger Method,where the heat units for a 24-hour period are: ##EQU1##

The highest maximum temperature used is 86° F. and the lowest minimumtemperature used is 50° F. For each inbred or hybrid it takes a certainnumber of GDUs to reach various stages of plant development.

GDU SLK=GDU TO SILK. The number of growing degree units required for aninbred line or hybrid to have approximately 50 percent of the plantswith silk emergence from time of planting. Growing degree units arecalculated by the Barger Method as given in GDU SHD definition.

GRN QUL=GRAIN QUALITY. This is a 1 to 9 rating for the general qualityof the shelled grain as it is harvested based on such factors as thecolor of the harvested grain, any mold on the grain, and any crackedgrain. High scores indicate good grain quality.

KER LB=KERNELS PER POUND. This is the number of kernels per 0.1 pound.

KSZ L=KERNEL SIZE LARGE. Percentage by weight of shelled corn thatpasses through a screen with 25/64 inch diameter openings but does notpass through a screen with 22/64 inch diameter openings.

KSZ MF=KERNEL SIZE MEDIUM FLAT. Percentage by weight of shelled cornthat passes through a screen with 22/64 inch diameter openings and ascreen with 13/64 inch wide slot screen but does not pass through ascreen with 18.5/64 inch diameter openings.

KSZ MR=KERNEL SIZE MEDIUM ROUND. Percentage by weight of shelled cornthat passes through a screen with 22/64 inch diameter openings but doesnot pass through a 13/64 inch wide slot screen or a screen with 18.5/64inch diameter openings.

KSZ S=KERNEL SIZE SMALL. Percentage by weight of shelled corn thatpasses through a screen with 18.5/64 inch diameter openings but does notpass through a screen with 16/64 inch diameter openings.

KSZ TIP=KERNEL SIZE TIPS. Percentage by weight of shelled corn thatpasses through a screen with 16/64 inch diameter openings.

KSZ XL=KERNEL SIZE EXTRA LARGE. Percentage by weight of shelled cornthat does not pass through a screen with 25/64 inch diameter openings.

MST=HARVEST MOISTURE. The moisture is the actual percentage moisture ofthe grain at harvest.

PLT HT=PLANT HEIGHT. This is a measure of the height of the plant fromthe ground to the tip of the tassel in inches.

POL WT=POLLEN WEIGHT. This is the weight of pollen per 100 plants takenon a plot basis. ABS refers to data in absolute, and % MN refers to datapresented as percentage of experimental mean.

PRM=PREDICTED RM. This trait, predicted relative maturity (RM), is basedon the harvest moisture of the grain. The relative maturity rating isbased on a known set of checks and utilizes standard linear regressionanalyses and is referred to as the Minnesota Relative Maturity RatingSystem.

RT LDG=ROOT LODGING. Root lodging is the percentage of plants that donot root lodge; plants that lean from the vertical axis at anapproximately 30° angle or greater would be counted as root lodged.

SCT GRN=SCATTER GRAIN. A 1 to 9 visual rating indicating the amount ofscatter grain (lack of pollination or kernel abortion) on the ear. Thehigher the score the less scatter grain.

SDG VGR=SEEDLING VIGOR. This is the visual rating (1 to 9) of the amountof vegetative growth after emergence at the seedling stage(approximately five leaves). A higher score indicates better vigor.

SEL IND=SELECTION INDEX. The selection index gives a single measure ofthe hybrid's worth based on information for up to five traits. A cornbreeder may utilize his or her own set of traits for the selectionindex. One of the traits that is almost always included is yield. Theselection index data presented in the tables represent the mean valueaveraged across testing stations.

STA GRN=STAY GREEN. Stay green is the measure of plant health near thetime of black layer formation (physiological maturity). A high scoreindicates better late-season plant health.

STK CNT=NUMBER OF PLANTS. This is the final stand or number of plantsper plot.

STK LDG=STALK LODGING. This is the percentage of plants that did notstalk lodge (stalk breakage) as measured by either natural lodging orpushing the stalks and determining the percentage of plants that breakbelow the ear.

TAS BLS=TASSEL BLAST. A 1 to 9 visual rating was used to measure thedegree of blasting (necrosis due to heat stress) of the tassel at timeof flowering. A 1 would indicate a very high level of blasting at timeof flowering, while a 9 would have no tassel blasting.

TAS SZ=TASSEL SIZE. A 1 to 9 visual rating was used to indicate therelative size of the tassel. The higher the rating the larger thetassel.

TAS WT=TASSEL WEIGHT. This is the average weight of a tassel (grams)just prior to pollen shed.

TEX EAR=EAR TEXTURE. A 1 to 9 visual rating was used to indicate therelative hardness (smoothness of crown) of mature grain. A 1 would bevery soft (extreme dent) while a 9 would be very hard (flinty or verysmooth crown).

TILLER=TILLERS. A count of the number of tillers per plot that couldpossibly shed pollen was taken. Data is given as percentage of tillers:number of tillers per plot divided by number of plants per plot.

TST WT=TEST WEIGHT UNADJUSTED. The measure of the weight of the grain inpounds for a given volume (bushel).

TST WTA=TEST WEIGHT ADJUSTED. The measure of the weight of the grain inpounds for a given volume (bushel) adjusted for percent moisture.

YLD=YIELD. It is the same as BU ACR ABS.

YLD SC=YIELD SCORE. A 1 to 9 visual rating was used to give a relativerating for yield based on plot ear piles. The higher the rating thegreater visual yield appearance.

CLN=Corn Lethal Necrosis (MCMV=Maize Chlorotic Mottle Virus andMDMV=Maize Dwarf Mosaic Virus): Visual rating (1-9 score) where a "1" isvery susceptible and a "9" is very resistant.

MDM CPX=Maize Dwarf Mosaic Complex (MDMV=Maize Dwarf Mosaic Virus &MCDV=Maize Chlorotic Dwarf Virus): Visual rating (1-9 score) where a "1"is very susceptible and a "9" is very resistant.

COM SMT=Common Smut (Ustilago maydis): Percentage of plants that did nothave infection.

ANT ROT=Anthracnose Stalk Rot (Colletotrichum graminicola): Visualrating (1-9 score) where a "1" is very susceptible and a "9" is veryresistant.

SLF BLT=Southern Leaf Blight (Bipolaris maydis, Helminthosporiummaydis): Visual rating (1-9 score) where a "1" is very susceptible and a"9" is very resistant.

NLF BLT=Northern Leaf Blight (Exserohilum turcicum, H. turcicum): Visualrating (1-9 score) where a "1" is very susceptible and a "9" is veryresistant.

HC BLT=Helminthosporium Carbonum Leaf Blight (Bipolariszeicola, H.carbonum): Visual rating (1-9 score) where a "1" is very susceptible anda "9" is very resistant.

COM RST=Common Rust (Puccinia sorghi): Visual rating (1-9 score) where a"1" is very susceptible and a "9" is very resistant.

SO RST=Southern Rust (Puccinia polysora): Visual rating (1-9 score)where a "1" is very susceptible and a "9" is very resistant.

EYE SPT=Eyespot (Kabatiella zeae : Visual rating (1-9 score) where a "1"is very susceptible and a "9" is very resistant.

GLF SPT=Gray Leaf Spot (Cercospora zeae-maydis): Visual rating (1-9score) where a "1" is very susceptible and a "9" is very resistant.

STW WLT=Stewart's Wilt (Erwinia stewartii): Visual rating (1-9 score)where a "1" is very susceptible and a "9" is very resistant.

GOS WLT=Goss's Wilt (Corynebacterium nebraskense): Visual rating (1-9score where a "1" is very susceptible and a "9" is very resistant.

HD SMT=Head Smut (Spacelotheca reiliana): Percentage of plants that didnot have infection.

DNY MIL=Downy Mildew (Peronosclerospora sorghi): Percentage of plantsthat did not have infection.

FUS EAR=Fusarium Ear Mold (Fusarium moniliforme): Percentage of plantsthat did not have infection.

EAR MLD=General Ear Mold: Visual rating (1-9 score) where a "1" very issusceptible and a "9" is very resistant. This is based on overall ratingfor ear mold of mature ears without determining specific mold organism,and may not be predictive for a specific ear mold.

ECB DPE=Dropped ears due to European Corn Borer (Ostrinia nubilalis):Percentage of plants that did not drop ears under second brood cornborer infestation.

ECB 2SC=European Corn Borer Second Brood (Ostrinia nubilalis): Visualrating (1-9 score) of post flowering damage due to infestation byEuropean Corn Borer. A "1" is very susceptible and a "9" is veryresistant.

ECB 1LF=European Corn Borer First Brood (Ostrinia nubilalis): Visualrating (1-9 score) of pre-flowering leaf feeding by European Corn Borer.A "1" is very susceptible and a "9" is very resistant.

ECB 2IT=European Corn Borer Second Brood Tunneling (Ostrinia nubilalis):The average inches of tunneling in the stalk due to second brood(post-flowering) European Corn Borer infestation. Determined bysplitting stalks with a knife, from four internodes above the ear to theground.

DETAILED DESCRIPTION OF THE INVENTION

Inbred Corn Line PHK35 is a yellow, dent corn inbred with superiorcharacteristics and provides an acceptable female parental line incrosses for producing first generation F₁ corn hybrids. The inbred isadapted over most regions of the United States. The inbred can be usedto produce hybrids from approximately 107-127 relative maturity based onthe Minnesota Relative Maturity Rating System for harvest moisture ofgrain. PHK35 may be used as either a male or female parent. As a femaleit has average yields, a very good cold test and acceptable kernel size.It sheds an adequate amount of pollen to be acceptable as a male.

The inbred has shown uniformity and stability within the limits ofenvironmental influence for all the traits as described in the VarietyDescription Information (Table 1) that follows. Most of the data in theVariety Description Information was collected at Johnston, Iowa. Theinbred has been self-pollinated and ear-rowed a sufficient number ofgenerations with careful attention paid to uniformity of plant type toensure homozygosity and phenotypic stability. The line has beenincreased both by hand and in isolated fields with continued observationfor uniformity. No variant traits have been observed or are expected inPHK35.

Inbred corn line PHK35, being substantially homozygous, can bereproduced by planting seeds of the line, growing the resulting cornplants under self-pollinating or sib-pollinating conditions withadequate isolation, and harvesting the resulting seed, using techniquesfamiliar to the agricultural arts.

                  TABLE 1                                                         ______________________________________                                        PHK35                                                                         VARIETY DESCRIPTION INFORMATION                                               ______________________________________                                        Type: Dent   Region Best Adapted: Most Regions                                A. Maturity:                                                                            Averaged across maturity zones. Zone: 0                             INBRED =               PHK35                                                  Heat Unit Shed:         1500                                                  Heat Unit Silk:         1540                                                  No. Reps:              68                                                     HEAT UNITS =                                                                   ##STR1##                                                                     ______________________________________                                         *If maximum is greater than 86 degrees fahrenheit, then 86 is used and if     minimum is less than 50, then 50 is used. Heat units accumulated daily an     can not be less than 0.                                                  

B. Plant Characteristics:

Plant height (to tassel tip): 239 cm

Length of top ear internode: 13 cm

Number of ears per stalk: Single

Ear height to base of top ear : 92 cm

Number of tillers: None

Cytoplasm type: Normal

C. Leaf:

Color: (WF9) Medium Green

Angle from Stalk:<30 degrees

Marginal Waves: (WF9) Few

Number of Leaves (mature plants):18

Sheath Pubescence: (W22) Light

Longitudinal Creases: (OH56A) Few

Length (Ear node leaf): 79 cm

Width (widest point, ear node leaf): 9 cm

D. Tassel:

Number lateral branches: 7

Branch Angle from central spike: 30-60 degrees

Pollen Shed: Medium based on pollen yield test (95% of experiment mean)

Peduncle Length (top leaf to basal branches): 21 cm

Anther Color: Reddish purple

Glume Color: Green

E. Ear (Husked Ear Data Except When Stated Otherwise):

Length: 15 cm

Weight: 69 gm

Mid-point Diameter: 41 mm

Silk Color: Salmon

Husk Extension (Harvest stage): Long (8-10 cm beyond ear tip)

Husk Leaf: Long (>15 cm)

Taper of Ear: Slight Taper

Position of Shank (dry husks): Horizontal

Kernel Rows: Distinct, slightly curved, Number=16

Husk Color (fresh): Light Green

Husk Color (dry): Buff to Light Brown

Shank Length: 12 cm

Shank (No. of internodes): 7

F. Kernel (Dried):

Size (from ear mid-point)

Length: 10 mm

Width: 7 mm

Thick: 5 mm

Shape Grade (% rounds): 20-40 % medium rounds based on

Parent Test Data

Pericarp Color: Colorless

Aleurone Color: Homozygous Yellow

Endosperm Color: Yellow

Endosperm Type: Normal Starch

Gm Wt/100 Seeds (unsized): 20 9m

G. Cob:

Diameter at mid-point: 25 mm

Strength: $trong

Color: White

H. Diseases:

Corn Lethal Necrosis (MCMV=Maize Chlorotic Mottle Virus and MDMV=MaizeDwarf Mosaic Virus): Susceptible

Maize Dwarf Mosaic Complex (MDMV & MCDV=Maize Chlorotic Dwarf Virus):Susceptible

Anthracnose Stalk Rot (C. Graminicola): Intermediate

S. Leaf Blight (H. Maydis): Intermediate

N. Leaf Blight (H. Turcicum): Susceptible

Carbonum Leaf Blight (H. Carbonum): Intermediate

Common Rust (P. Sorghi): Intermediate

Eye Spot (K. Zeae): Intermediate

Gray Leaf Spot C. Zeae) Susceptible

Stewarts Wilt (E. Stewartii): Intermediate

Goss's Wilt (C. Nebraskense): Resistant

Common Smut (U. Maydis): Resistant

Head Smut (S. Reiliana): Resistant

Downy Mildew (S. Sorghi): Resistant

Fusarium Ear Mold (F. Moniliforme): Intermediate

I. Insects:

ECB1LF European Corn Borer-1 Leaf Damage (Pre-flowering):

Susceptible

ECB2SC European Corn Borer-2 (Post-flowering):

Intermediate

    ______________________________________                                        J. Variety Most Closely Resembling:                                                  Character                                                                             Inbred                                                         ______________________________________                                               Maturity                                                                              PHK29                                                                 Usage   PHK29                                                          ______________________________________                                    

PHK29 (PVP certificate 8700214 and U.S. Pat. No. 4,812,600) is a PioneerHi-Bred International, Inc. proprietary inbred.

Items B, C, D, E, F, and G are based on a maximum of three reps of dataprimarily from Johnston, Iowa in 1987, 1988, and on descriptioninformation from the maintaining station.

                  TABLE 2                                                         ______________________________________                                        ELECTROPHORESIS RESULTS                                                       Isozyme Genotypes for PHK35                                                   Isozyme data was generated for inbred corn line PHK35                         according to the procedure described in Goodman, M. M. and                    Stuber, C. M. "Genetic identification of lines and crosses                    using isoenzyme electrophoresis," Proceedings of the Thirty-                  Fifth Annual Corn and Sorghum Industry Research                               Conference, Chicago, Illinois (1980).                                         Alleles Present                                                                       Loci  PHK35                                                           ______________________________________                                                ACP1  2                                                                       ADH1  4                                                                       CAT3  9                                                                       DIA1  8                                                                       GOT1  4                                                                       GOT2  2                                                                       GOT3  4                                                                       IDH1  4                                                                       IDH2  4                                                                       MDH1  6                                                                       MDH2  3.5                                                                     MDH3  16                                                                      MDH4  12                                                                      MDH5  12                                                                      MMM   4                                                                       PGM1  9                                                                       PGM2  4                                                                       PGD1  2                                                                       PGD2  5                                                                       PHI1  4                                                               ______________________________________                                    

INDUSTRIAL APPLICABILITY

This invention also is directed to methods for producing a corn plant bycrossing a first parent corn plant with a second parent corn plantwherein the first or second parent corn plant is an inbred corn plantfrom the line PHK35. Further, both first and second parent corn plantscan come from the inbred corn line PHK35. Thus, any such methods usingthe inbred corn line PHK35 are part of this invention: selfing,backcrosses, hybrid production, crosses to populations, and the like.All plants produced using inbred corn line PHK35 as a parent are withinthe scope of this invention. Advantageously, the inbred corn line isused in crosses with other, different, corn inbreds to produce firstgeneration (F ) corn hybrid seeds and plants with superiorcharacteristics.

As used herein, the terms "plant and plant parts" include plant cells,plant protoplasts, plant cell tissue culture from which corn plants canbe regenerated, plant calli, plant clumps, and plant cells that areintact in plants or parts of plants, such as embryos, pollen, flowers,kernels, ears, cobs, leaves, husks, stalks, roots, root tips, anthers,silk and the like.

Tissue culture of corn is described in European Patent Application,publication 160,390, incorporated herein by reference. Corn tissueculture procedures are also described in Green and Rhodes, "PlantRegeneration in Tissue Culture of Maize," Maize for Biological Research(Plant Molecular Biology Association, Charlottesville, Va. 1982, at367-372. Thus, another aspect of this invention is to provide cellswhich upon growth and differentiation produce the inbred line PHK35.

The utility of inbred line PHK35 also extends to crosses with otherspecies. Commonly, suitable species will be of the family Graminaceae,and especially of the genera Zea, Tripsacum, Coix, Schlerachne,Polytoca, Chionachne, and Trilobachne, of the tribe Maydeae. Of these,Zea and Tripsacum, are most preferred. Potentially suitable for crosseswith PHK35 may be the various varieties of grain sorghum, Sorghumbicolor (L.) Moench.

Corn is used as human food, livestock feed, and as raw material inindustry. The food uses of corn, in addition to human consumption ofcorn kernels, include both products of dry- and wet-milling industries.The principal products of corn dry milling are grits, meal and flour.The corn wet-milling industry can provide corn starch, corn syrups, anddextrose for food use. Corn oil is recovered from corn germ, which is aby-product of both dry- and wet-milling industries.

Corn, including both grain and non-grain portions of the plant, is alsoused extensively as livestock feed, primarily for beef cattle, dairycattle, hogs, and poultry.

Industrial uses of corn are mainly from corn starch from the wet-millingindustry and corn flour from the dry-milling industry. The industrialapplications of corn starch and flour are based on functionalproperties, such as viscosity, film formation, adhesive properties, andability to suspend particles. The corn starch and flour have applicationin the paper and textile industries. Other industrial uses includeapplications in adhesives, building materials, foundry binders, laundrystarches, explosives, oil-well muds, and other mining applications.

Plant parts other than the grain of corn are also used in industry.Stalks and husks are made into paper and wallboard and cobs are used forfuel and to make charcoal.

The seed of inbred corn line PHK35, the plant produced from the inbredseed, the hybrid corn plant produced from the crossing of the inbred,hybrid seed, and various parts of the hybrid corn plant can be utilizedfor human food, livestock feed, and as a raw material in industry.

EXAMPLE

INBRED AND HYBRID PERFORMANCE OF PHK35

In the examples that follow the traits and characteristics of inbredcorn line PHK35 are given as a line and in hybrid combination. The datacollected on inbred corn line PHK35 is presented for the keycharacteristics and traits.

The results in Table 3 compare PHK35 to PHK29. PHK29 (PVP Certificate#8700214, U.S. Pat. No. 4,812,600) is an important inbred that would beused in many of the same areas that PHK35 would be used and would crosswell with many of the same inbred lines. This data was collected overfour years of research testing. The results show that the two inbredsdiffer significantly for a number of traits. PHK35 has a higher coldtest score, better early stand count, and better grain quality thanPHK29. PHK35 sheds greater amounts of pollen than PHK29 and would be abetter male parent in hybrid production. PHK35 also showed greaterresistance to ear mold than PHK29.

The results in Table 4 compare PHK35 to PHK29 crossed to the same inbredtesters. The results show that the two lines differ significantly for anumber of traits in hybrid combination. PHK35 hybrids tend to havebetter performance in the eastern Corn Belt while PHK29 hybrids tend tohave better performance in the western Corn Belt. PHK35 hybrids weretaller than the PHK29 hybrids. The PHK35 hybrids scored 101 percent ofthe mean for resistance to stalk lodging and scored 104 percent of themean for grain quality compared to 98 and 102 percent of the mean,respectively, for the PHK29 hybrids. PHK35 has given good performance inspecific hybrid combinations.

The results in Table 5A compare a PHK35 hybrid to Pioneer® brand hybrid3379. These two hybrids have one parent in common that is not PHK35.This data has been collected over 3 years of research testing. Pioneer®brand 3379 has been a very popular hybrid. PHK35 hybrid will be utilizedin some of the same areas that 3379 is currently being used. Thecomparison shows that the PHK35 hybrid has greater resistance to stalklodging, a higher stay green score, a higher grain quality score, andbetter test weight than 3379.

The results in Table 5B compare a PHK35 hybrid to Pioneer® brand hybridto 3569. These hybrids have one parent in common that is not PHK35. Thisdata has been collected over 3 years of research testing. Pioneer® brand3569 has been a popular hybrid in the Central and Western areas. PHK35hybrid will be utilized in some of the same areas that 3569 is currentlybeing used but is better adapted to the easter Corn Belt. The comparisonshows that the PHK35 hybrid has a 2.2 bu/acre yield increase and was0.4% dryer for harvest grain moisture compared to 3569. The results alsoshow that the PHK35 hybrid scored higher on resistance to stalk lodgingthan 3569, had a higher stay green score, better grain quality, andhigher grain test weight than 3569.

The results in Table 6 compare a PHK35 hybrid with Pioneer® brand hybrid3475. These hybrids have one parent in common that is not PHK35. Thisdata has been collected over 3 years of research testing. Pioneer® brand3475 has been a very popular hybrid. PHK35 hybrid will be utilized inmuch of the same areas that 3475 is currently being used. The comparisonshows that the PHK35 hybrid has a 6.2 bu/acre yield advantage over 3475,and is 1.5% lower for harvest moisture of the grain. The PHK35 hybridalso has a higher stay green score, with a highly significant testweight and grain quality advantage over 3475. it is a significantlytaller and higher eared hybrid which makes it more attractive as asilage hybrid. The PHK35 has better stand establishment in the springthan 3475.

                                      TABLE 3                                     __________________________________________________________________________    PAIRED INBRED COMPARISON DATA                                                 INBRED #1 - PHK35                                                             INBRED #2 - PHK29                                                             __________________________________________________________________________                BU    BU    BAR  BRT EAR EAR EST   CLD   CLD   DRP                        VAR ACR   ACR   PLT  STK HT  SZ  CNT   TST   TST   EAR                YEAR    #   ABS   % MN  ABS  ABS ABS ABS ABS   ABS   % MN  ABS                __________________________________________________________________________    TOTAL SUM                                                                             1   65.0  99    82.8 95.6                                                                              32.3                                                                              5.4 42.9  91.8  108   100.0                      2   79.5  124   87.9 94.4                                                                              32.6                                                                              5.8 40.5  84.8  100   99.9                       LOCS                                                                              70    70    49   13  59  23  163   31    31    45                         DIFF                                                                              14.5  25    5.1  1.2 0.3 0.4 2.5   7.0   9     0.0                        PROB                                                                              .000# .000# .071*                                                                              .582                                                                              .680                                                                              .255                                                                              .000# .010+ .013+ .651               __________________________________________________________________________                TIL  GDU GDU   GRN   KER   KSZ   KSZ   KSZ   KSZ                          VAR LER  SHD SLK   QUL   LB    XL    L     MR    MF                   YEAR    #   ABS  ABS ABS   ABS   ABS   ABS   ABS   ABS   ABS                  __________________________________________________________________________    TOTAL SUM                                                                             1   1.3   150.8                                                                            155.8 7.5   174.6 0.0   3.1   30.6  24.6                         2   1.9  151.0                                                                             154.9 6.7   151.6 0.3   18.5  37.0  31.0                         LOCS                                                                              52   129 104   53    26    16    16    16    16                           DIFF                                                                              0.6  0.1 0.9   0.8   23.1  0.3   15.4  6.4   6.4                          PROB                                                                              .415 .717                                                                              .058* .000# .000# .055* .000# .037+ .034+                __________________________________________________________________________                KSZ   KSZ         PLT   POL   POL   POL   RT  TAS                         VAR S     TIP   MST   HT    WT    WT    SC    LDG BLS                 YEAR    #   ABS   ABS   ABS   ABS   ABS   % MN  ABS   ABS ABS                 __________________________________________________________________________    TOTAL SUM                                                                             1   36.7  5.5   20.5  84.9  169.4 100   4.8   91.0                                                                              8.7                         2   12.0  0.9   20.8  81.5  150.8 89    5.3   94.1                                                                              9.0                         LOCS                                                                              16    15    75    61    6     6     54    29  6                           DIFF                                                                              24.7  4.5   0.3   3.4   18.6  11    0.5   3.1 0.3                         PROB                                                                              .000# .000# .032+ .000# .002# .001# .002# .289                                                                              .363                __________________________________________________________________________                TAS  TAS  TEX   TST   SCT    SDG  STA   STK  STK                          VAR SZ   WT   EAR   WT    GRN   VGR   GRN   CNT  LDG                  YEAR    #   ABS  ABS  ABS   ABS   ABS   ABS   ABS   ABS  ABS                  __________________________________________________________________________    TOTAL SUM                                                                             1   5.3  3.5  7.0   59.1  7.0   5.3   5.6   33.9 93.7                         2   4.9  3.4  5.8   57.7  5.8   5.8   6.9   33.8 95.8                         LOCS                                                                              43   6    18    71    35    82    72    193  56                           DIFF                                                                              0.3  0.1  1.2   1.4   1.1   0.5   1.4   0.1  2.1                          PROB                                                                              .074 .157 .015+ .000# .000# .003# .000# .766 .041+                __________________________________________________________________________                YLD   ANT    COM COM EAR   ECB ECB ECB ECB EYE FUS                        VAR SC    ROT CLN                                                                              RST SMT MLD   DPE 1LF 2SC 2IT SPT EAR                YEAR    #   ABS   ABS ABS                                                                              ABS ABS ABS   ABS ABS ABS ABS ABS ABS                __________________________________________________________________________    TOTAL SUM                                                                             1   5.3   3.7 3.5                                                                              6.0 0.0 7.7   97.2                                                                              4.5 5.7 16.2                                                                              5.1 75.8                       2   6.2   4.0 3.5                                                                              5.0 0.0 6.6   95.0                                                                              4.4 6.2 11.0                                                                              5.3 64.8                       LOCS                                                                              37    3   2  1   1   32    6   28  20  2   6   5                          DIFF                                                                              0.9   0.3 0.0                                                                              1.0 0.0 1.1   2.2 0.2 0.5 5.2 0.2 11.0                       PROB                                                                              .002# .423                                                                              1.00       .001# .175                                                                              .559                                                                              .119                                                                              .155                                                                              .235                                                                              .481               __________________________________________________________________________                              GLF GOS HC  HD   MDM NLF SLF SO STW                                       VAR SPT WLT BLT SMT  CPX BLT BLT RST                                                                              WLT                               YEAR    #   ABS ABS ABS ABS  ABS ABS ABS ABS                                                                              ABS                 __________________________________________________________________________                  TOTAL SUM                                                                             1   3.3 7.8 5.9 100.0                                                                              2.3 3.5 5.1 6.0                                                                              6.2                                       2   3.8 7.7 5.5 98.2 2.2 3.5 5.7 5.5                                                                              8.0                                       LOCS                                                                              14  3   4   8    3   11  6   1  3                                         DIFF                                                                              0.5 0.2 0.4 1.8  0.2 0.1 0.6 0.5                                                                              1.8                                       PROB                                                                              .251                                                                              .423                                                                              .215                                                                              .082*                                                                              .874                                                                              .829                                                                              .341   .053*               __________________________________________________________________________     * = 10% SIG                                                                   + = 5% SIG                                                                    # = 1% SIG                                                               

                                      TABLE 4                                     __________________________________________________________________________    Average Inbred by Tester Performance Comparing PHK29 to PHK35 crossed         to the same Inbred Testers and Grown in the Same Experiments. All             Values are Expressed as percent of the experiment mean except Predicted       RM, Selection Index, and Yield (Bu./Ac.).                                     __________________________________________________________________________                     SEL                                                                              BU       GDU STK RT  BAR                                                                              STA                                      Inbred                                                                              PRM IND                                                                              ACR                                                                              YLD                                                                              MST                                                                              SHD LDG LDG PLT                                                                              GRN                               __________________________________________________________________________    TOTAL  REPLIC.                                                                             217 225                                                                              225                                                                              225                                                                              235                                                                               65 223  74 100                                                                              149                               MEAN WTS                                                                             PHK29 115 102                                                                              122                                                                              102                                                                              100                                                                              100  98 102 102                                                                              100                               MEAN WTS                                                                             PHK35 115 104                                                                              122                                                                              102                                                                               98                                                                              100 101 100  99                                                                               98                                      DIFF.  1   2     0  2  1   3   4   4  1                                __________________________________________________________________________                      TST COB                                                                              GRN SDG EST                                                                              PLT                                                                              EAR                                                                              DRP                                                                              BRT                                          Inbred                                                                              WTA SC QUL VGR CNT                                                                              HT HT EAR                                                                              STK                              __________________________________________________________________________    TOTAL       REPLIC.                                                                             235  24                                                                              129 139 148                                                                              127                                                                              127                                                                              189                                                                               14                              MEAN WTS    PHK29 100  88                                                                              102  95  99                                                                               99                                                                               98                                                                              100                                                                               99                              MEAN WTS    PHK35 101 100                                                                              104  93 101                                                                              103                                                                              104                                                                              100                                                                              100                                          DIFF.  1   12                                                                               2   2   2  4  6  0  1                               __________________________________________________________________________

                                      TABLE 5A                                    __________________________________________________________________________    #1 - PHK35 HYBRID                                                             #2 - PIONEER ® BRAND 3379                                                 __________________________________________________________________________                          BU          GDU   STK   RT   BAR   STA                       VAR  SEL         ACR   MST   SHD   LDG   LDG  PLT   GRN                  YEAR #    IND   PRM   ABS   ABS   ABS   ABS   ABS  ABS   ABS                  __________________________________________________________________________    TOTAL                                                                              1    102   122   138.0 21.0  143.7 95.7  95.3 93.5  6.4                  SUM  2    105   120   140.8 20.3  142.9 93.2  94.9 95.8  5.9                       LOCS 49    49    253   256   65    227   110  74    166                       DIFF 3     2     2.8   0.7   0.8   2.5   0.4  2.2   0.6                       PROB .032+ .000# .009# .000# .007# .000# .630 .026+ .000#                __________________________________________________________________________                   TST   COB GRN   SDG   EST   PLT   EAR   DRP BRT                          VAR  WTA   SC  QUL   VGR   CNT   HT    HT    EAR STK                YEAR      #    ABS   ABS ABS   ABS   ABS   ABS   ABS   ABS ABS                __________________________________________________________________________    TOTAL     1    58.4  6.5 7.4   5.5   59.1  103.6 45.8   99.6                                                                             93.3               SUM       2    57.3  6.5 6.9   5.9   60.7  101.9 44.1  99.6                                                                              93.3                         LOCS 250   26  155   138   194   135   136   134 15                           DIFF 1.1   0.1 0.6   0.4   1.6   1.7   1.7   0.0 0.0                          PROB .000# .772                                                                              .000# .000# .000# .000# .000# .821                                                                              .991               __________________________________________________________________________     * = 10% SIG                                                                   + = 5% SIG                                                                    # = 1% SIG                                                               

                                      TABLE 5B                                    __________________________________________________________________________    HYBRID #1 - HYBRID PHK35                                                      HYBRID #2 - PIONEER ® BRAND 3569                                          __________________________________________________________________________                         BU         GDU STK   RT  BAR  STA   TST                          VAR SEL      ACR  MST   SHD LDG   LDG PLT  GRN   WTA                  YEAR    #   IND PRM  ABS  ABS   ABS ABS   ABS ABS  ABS   ABS                  __________________________________________________________________________    TOTAL SUM                                                                             1   105 106  136.1                                                                              18.7  137.5                                                                             93.5  95.1                                                                              93.1 5.1   59.4                         2   104 107  133.9                                                                              19.1  136.9                                                                             89.5  95.5                                                                              93.5 4.6   57.8                         LOCS                                                                              28  31   163  163   36  156   57  35   90    162                          DIFF                                                                              1   1    2.2  0.4   0.6 4.1   0.4 0.4  0.6   1.6                          PROB                                                                              .814                                                                              .026+                                                                              .066*                                                                              .000# .195                                                                              .000# .692                                                                              .676 .000# .000#                __________________________________________________________________________                           COB GRN   SDG   EST PLT   EAR   DRP BRT                                   VAR SC  QUL   VGR   CNT HT    HT    EAR STK                           YEAR    #   ABS ABS   ABS   ABS ABS   ABS   ABS ABS                __________________________________________________________________________               TOTAL SUM                                                                             1   6.7 7.4   5.8   64.1                                                                              102.7 44.8  98.2                                                                              97.7                                  2   6.8 6.6   6.3   64.0                                                                              98.8  43.7  98.7                                                                              98.2                                  LOCS                                                                              6   88    67    108 71    71    121 20                                    DIFF                                                                              0.1 0.8   0.5   0.1 3.9   1.1   0.4 0.5                                   PROB                                                                              .625                                                                              .000# .004# .758                                                                              .000# .011+ .108                                                                              .681               __________________________________________________________________________     * = 10% SIG                                                                   + = 5% SIG                                                                    # = 1% SIG                                                               

                                      TABLE 6                                     __________________________________________________________________________    #1 - PHK35 HYBRID                                                             #2 - PIONEER ® BRAND 3475                                                 __________________________________________________________________________                            BU          GDU   STK  RT   BAR  STA                          VAR SEL         ACR   MST   SHD   LDG  LDG  PLT  GRN                  YEAR    #   IND   PRM   ABS   ABS   ABS   ABS  ABS  ABS  ABS                  __________________________________________________________________________    TOTAL SUM                                                                             1   106   107   129.4 18.8  138.0 92.5 95.0 93.5 5.0                          2   98    112   123.2 20.3  135.0 92.0 96.4 93.0 4.7                          LOCS                                                                              44    46    238   239   57    222  82   48   136                          DIFF                                                                              8     5     6.2   1.5   3.1   0.5  1.4  0.6  0.3                          PROB                                                                              .008# .000# .000# .000# .000# .286 .072*                                                                              .286 .011+                __________________________________________________________________________                   TST   COB GRN   SDG EST   PLT   EAR   DRP   BRT                           VAR WTA   SC  QUL   VGR CNT   HT    HT    EAR   STK                YEAR       #   ABS   ABS ABS   ABS ABS   ABS   ABS   ABS   ABS                __________________________________________________________________________    TOTAL SUM  1   59.2  6.9 7.3   5.9 64.1  101.4 44.6   98.5 97.9                          2   57.7  7.3 6.7   5.8 60.9  92.8  40.2  99.1  98.7                          LOCS                                                                              239   16  164   116 154   111   111   169   21                            DIFF                                                                              1.6   0.3 0.6   0.1 3.2   8.7   4.3   0.6   0.8                           PROB                                                                              .000# .196                                                                              .000# .524                                                                              .000# .000# .000# .024+ .452               __________________________________________________________________________     * = 10% SIG                                                                   + = 5% SIG                                                                    # = 1% SIG                                                               

Deposits

Applicants have made available to the public without restriction adeposit of at least 2500 seeds of inbred PHK35 with the American TypeCulture Collection (ATCC), Rockville, Md. 20852 USA, ATCC Deposit No.75073. The seeds deposited with the ATCC are taken from the same depositmaintained by Pioneer Hi-Bred International Inc., 700 Capital Square,400 Locust Street, Des Moines, Iowa 50309 since prior to the filing dateof this application. The deposit will be maintained in the ATCCdepository, which is a public depository, for a period of 30 years, or 5years after the most recent request, or for the effective life of thepatent, whichever is longer, and will be replaced if it becomesnonviable during that period.

What is claimed is:
 1. Inbred corn seed designated PHK35 having ATCCaccession No.
 2. A corn plant produced by the seed of claim
 1. 3. Tissueculture of the plant of claim
 2. 4. Tissue culture according to claim 3comprising regenerable cells of a plant part selected from meristematictissue, anthers, leaves, embryos, protoplasts, and pollen.
 5. A cornplant regenerated from the regenerable cells of a tissue cultureaccording to claim
 4. 6. An inbred corn plant having all thephysiological and morphological characteristics of the seed of claim 1.7. A method to produce a novel hybrid corn seed comprising the stepsof:(a) planting in pollinating proximity seeds of corn inbred linesPHK35 and another inbred line; (b) cultivating corn plants resultingfrom said planting until the time the plants bear flowers; (c)emasculating the flowers of the plants of either inbred line; (d)allowing natural cross pollinating to occur between said inbred lines;and (e) harvesting seeds produced on said emasculated plants of theinbred line.
 8. An F₁ hybrid corn plant and seed thereof produced bycrossing an inbred corn plant according to claim 2 with another,different corn plant.